The present invention relates to the formation, handling, and application of lightweight strips, such as, but not limited to, medical test strips. Many medical, chemical and biological diagnostic tests and assays for laboratory and home use have been reduced to an optimally simple routine: immerse a test strip or stick into a liquid, and observe the change in color of the test strip or stick to read the results of the test. Tests that formerly required days of laboratory work may now be carried out in seconds, with a reliability factor that exceeds former, more time-consuming methods. Generally speaking, the strips or sticks (hereinafter, xe2x80x9cstripsxe2x80x9d) comprise long, narrow pieces of paper, plastic, laminates, or similar thin sheet material that carry one or more highly specific reagent, reactant, or assay compound distributed in the sheet material.
The sheet material may be manufactured in large amounts, generally as long webs of the sheet material wound on spools to form a compact roll. The roll is fabricated into the test strips by first cutting the web into discrete lengths, or cards, that are subsequently fed into a strip cutting machine. The strips thus formed are then manipulated, gathered, and packaged as is known in the prior art. For example, U.S. Pat. No. 5,057,309 describes an apparatus for cutting and assembling batches of diagnostic strips, and U.S. Pat. No. 5,816,030 describes a scoop assembly for gathering strips from a platen that receives the strips formed by a rotary knife assembly. Likewise, U.S. Pat. No. 6,089,000 depicts a strip handling assembly in which strips are formed by cutter assembly and then placed on an accumulator track, from which a variable, programmable number of strips may be removed and packaged.
For some uses, the strips discharged from a cutter assembly are not gathered and packaged; rather, it is necessary to handle each strip individually to place each strip in an device, such as, for example, a pregnancy test kit, or the like. Due to the low ratio of mass to surface area of individual strips, the strips can be extremely difficult to manipulate (grasp, translate, apply, etc.) separately. In addition, the materials from which the strips are formed (such as paper stock, thin plastic web, etc.) may easily accumulate static electricity charges. The effect of static electricity on the low mass, high surface area strips may greatly exceed gravitational force. Likewise, stray air currents can disrupt any well-designed handling machinery.
It may be noted that the strips typically are discharged from a rotary cutting assembly in parallel, closely spaced array, the spacing being no greater than the thickness of the rotary knives that cut each card into strips. It is difficult to handle individual strips when they are spaced so closely together. Thus the strips must be separated and spaced apart to permit access by automated machines that carry out manipulation of the individual strips.
The present invention generally comprises an apparatus for forming, separating, and manipulating individual test strips and the like, whereby the individual strips may be applied or installed as required for any finished product.
The apparatus includes a rotary cutting assembly having a plurality of rotary knives that convert a card into a plurality of closely spaced strips; i.e., virtually no lateral spacing between the strips. The strips are delivered onto a platen assembly which is provided with a plurality of parallel channels, each channel having a bottom surface that is inclined laterally (with respect to the longitudinal extent of the respective strip). The channels have a proximal portion where the strips are received from the cutting assembly. The bottom surface of the proximal portion of each channel is provided with a pair of vacuum suction holes to maintain strips thereat. Among the plurality of channels in the platen, every other channel (hereinafter, a T channel) is designed for translation of a strip therein from the proximal portion to a distal portion. Each T channel distal portion includes a pair of holes in the bottom surface through which vacuum suction is applied to retain the strips in their respective channels. Each T channel proximal portion includes in the bottom surface thereof a longitudinally extending slot.
The apparatus further includes a separator assembly that extends laterally to span all the channels of the platen assembly, and is adapted to be translated longitudinally and reciprocally between positions that are superjacent to the proximal and distal portions of the platen assembly. The separator assembly includes an upper containment plate having a bottom surface that is formed in generally complementary fashion to the channels of the platen assembly, and is spaced vertically therefrom a sufficient distance to define a narrow vertical space in each channel that receives in the proximal portion thereof a respective strip from the cutting assembly.
The separator assembly also includes a comb device, which is pivotally secured to the separator assembly at a distal edge thereof. The laterally extending proximal edge of the comb device supports a plurality of tines extending downwardly and dimensioned to be received in a respective T channel of the platen assembly. The comb device is driven reciprocally to rotate from an upper position in which the tines are clear of the T channels, to a lower position in which the tines are engaged in the T channels. Indeed, in the lower position each tine is sufficiently long and narrow to extend into the respective slot formed in the bottom surface of the proximal portion of each T channel.
In general, the separator assembly is driven to translate to the proximal position of the platen assembly. With the comb device rotated to the upper position, the cutter assembly is operated to discharge a plurality of strips into all the channels, the strips being received in the narrow vertical space between the channels and the upper containment plate. At this stage, all the proximal portions of all the channels are filled with strips in a parallel array. Vacuum is applied to the holes in the bottoms of the proximal portions to retain the strips in place. The comb device is then rotated to the lower position, in which each tine is received in a respective slot of a respective T channel, the tine being closely spaced to the proximal end of the respective strip. Thereafter, the separator assembly is translated to the distal portion of the platen assembly, as the vacuum suction is released at the proximal portions of the T channels. The tines push the strips in the T channels distally, so that every other strip of the plurality is urged to the distal portion of the platen assembly. Suction is then applied to the holes in the bottom surfaces of the distal portions of the T channels to retain the strips thereat. At this stage the plurality of strips has been divided into two groups: a proximal group situated in every other channel of the proximal portion of the platen assembly, and a distal group disposed in the distal portions of the T channels. The proximal group is exposed in the channels, while the distal group is obscured by the presence of the separator assembly thereat.
Another major component of the invention is a pick-and-place conveyor assembly disposed adjacent to the platen assembly. The pick-and-place conveyor includes a pickup head that is adapted to translate reciprocally between positions superjacent to the platen assembly and to a belt conveyor. The pickup head is provided with a plurality of suction cups connected to a vacuum source, the suction cups arranged in two parallel lines, with a paired relationship therebetween. Each pair of suction cups are disposed each to engage an opposed end of one strip. The pairs of suction cups are arrayed in downwardly pointing orientation, and spaced so that each pair engages one of the strips in the proximal group or distal group; that is, spaced apart a distance equal to two channel widths.
The pick-and-place conveyor is driven reciprocally between a position superjacent to a belt conveyor, and, alternately, superjacent to the proximal and distal portions of the platen assembly. The pick-and-place conveyor is actuated in synchronism with the separator assembly and the cutter assembly.
In general, the invention operates according to the following sequential steps to achieve the goal of increasing the spacing of the lightweight strips so that the strips may be accessed and engaged by further processing equipment. When the separator assembly is disposed at the proximal portion of the platen assembly, and the comb is rotated upwardly, the separator assembly may be resupplied with strips from the cutter assembly, one strip in each and every channel. At the same time, the pick-and-place conveyor translates to the distal portion of the platen assembly, and descends to grasp each of the strips disposed in the T channels. The pick-and-place conveyor then retracts vertically, and translates to a position superjacent to a belt conveyor. At the belt, conveyor, the pick-and-place conveyor descends so that the suction cups are disposed at the surface of the belt conveyor, and the suction is cut off to release the strips onto the belt conveyor.
While the pick-and-place conveyor is translated away from the proximal portion of the platen assembly, the comb is rotated to the lower position, and the separator assembly is translated longitudinally to push the strips in the T channels to the distal portion of the platen. The proximal group of strips, in the non-T channels, are exposed upwardly, and the pick-and-place conveyor is translated to the proximal portion of the platen to pick up the proximal group. The pickup head is indexed laterally a distance equal to the width of one channel, so that the suction cup array is in registration with the proximal group of strips in the non-T channels.
After the pick-and-place conveyor grasps and lifts the proximal strips, it is translated toward the belt conveyor. After the pick-and-place conveyor clears the proximal portion of the platen assembly, the separator assembly is translated to the proximal portion of the platen, and vacuum suction is applied to the distal portions of the T channels to hold the distal group strips therein. This distal group is thus exposed upwardly for access by the pick-and-place conveyor, which then may begin another cycle.
It is significant to note that the strips, when placed onto the belt conveyor, are spaced apart longitudinally a distance equal to the width of one channel on the platen. This spacing enables access to individual strips on the belt conveyor by further processing equipment. The pace of each cycle of the invention may be bounded by extrinsic factors. For example, the belt conveyor must move a sufficient distance for the pick-and-place conveyor to deposit each array of strips onto the belt, so that the reciprocal movement of the pick-and-place conveyor may limit the operational speed of the combined mechanisms of the invention.